1. Field of the Invention
The present invention relates to a job-submission-request apparatus and method, more specifically, a job-submission-request apparatus and method suitable for use in making a request of a plurality of job-submission apparatuses to submit a job.
2. Description of the Related Art
Up to this time, print jobs have been distributed among many printers by using a print server. When a single print server controls many print jobs, the load placed on the print server increases, which takes a long time until the sheet discharge of each of the print jobs is achieved. For preventing the above-described problem, a load-balancing environment (an environment created by using, for example, a network-load balancer) which allows for balancing the load placing on the print server by using plural print servers should be created.
The technology disclosed in Japanese Patent Laid-Open No. 2006-313442 is an example of known technologies used for a system configured to control printing in the above-described load-balancing environment. According to the technology disclosed in Japanese Patent Laid-Open No. 2006-313442, plural output servers (print servers) are provided and a management server is provided above the output servers, so as to manage the output servers. Then, the management server transmits data on an output request to the output server. The output server temporarily queues the output request and makes a single printer start a single print process. After the print process is started, the output server retrieves data yet to be printed from the management server and makes the printer execute printing based on the data yet to be printed. According to the known technologies, a load placed on an output server is balanced in the above-described manner and a management server controls the print order so that the print order is ensured.
According to the above-described known technology, however, the plural output servers are managed by the single management server controlling the print order. Therefore, no thought is given to balancing the load placed on the single management server. For printing data on many print jobs by using many printers distant from one another, the load placed on the management server becomes a serious risk. Therefore, achievement of a print system used in a load-balancing environment where plural print servers perform printing control including print-order ensuring so that the load balancing is performed by the entire print system has been demanded.
However, achieving the print system used in the above-described load-balancing environment presents the following problems.
Namely, when plural clients instruct the same printer to perform printing for a print job, it is often difficult to output the print jobs (sheet discharge) in the order in which the print instructions are provided.
For example, an example where a client instructs a printer a to print the first print job and the second print job in that order while a print server A submits a print job to a printer b other than the printer a and makes the printer b perform printing will be considered. In that case, a balancer configured to distribute processing among print servers may operate so that the first print job is assigned to the print server A and the second print job is assigned to the print server B. Consequently, the print server A submits the assigned first print job to the printer a after the print job is submitted to the printer b. Therefore, the second print job is submitted to the printer a before the first print job is submitted thereto. As a result, the sheet discharge (printing) of the second print job is completed before that of the first print job is completed, where the print instruction of the second print job is provided after that of the first print job is provided. As for print jobs intended for the same printer, the print server has to submit the print jobs to the same printer in the order of requests made by the client. Therefore, the above-described example where the print order is not ensured presents a serious problem. Further, it has been difficult to balance a load placed on a print server controlling the print order in addition to printing by using known technologies.
Thus, when a load-balancing environment where each of plural print servers (job-submission apparatuses) configured to submit a job to a printer (an output apparatus) can submit a job to any of plural printers (output apparatuses) is created according to known technologies, the following problem arises. Namely, if a client makes requests of the same printer (output apparatus) to output plural jobs, it may become difficult to submit the jobs to the printer (output apparatus) in the order in which the requests are made by the client.